Method for washing cooling or air conditioning circuits and device for carrying out said method

ABSTRACT

The invention relates to a method for washing cooling or air conditioning circuits, according to which a washing agent is conducted through said cooling or air conditioning circuit. Said agent dissolves and absorbs the soluble substances that adhere to the cooling or air conditioning circuits and discharges the mechanical contaminants. The washing agent is conducted through the cooling or air conditioning circuit that is washed in a closed cycle without escaping into the environment, by the pressure differential between the pressure chamber and the distillation chamber and is returned to the pressure chamber after being cleaned in the distillation chamber, compressed by a compressor and cooled in a condenser. The invention also relates to a device for washing cooling or air conditioning circuits, said device consisting of a pressure chamber containing a washing agent. The outlet pipe for fluid of the pressure chamber is connected to the cooling or air conditioning circuit that is washed. A compressor and a condenser, which is connected to a supply line for fluid to the pressure chamber, are connected upstream of said chamber. A distillation chamber is connected between the cooling or air conditioning circuit that is washed and the compressor and inert gas that is compressed by the washing agent is contained in the pressure chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national counterpart application ofinternational application serial no. PCT/CZ2005/000046 filed Jun. 2,2005, which claims priority to Czech Republic application serial no. PV2004-678 filed Jun. 2, 2004.

The invention relates to a method for flushing cooling orair-conditioning circuits, during which the cooling or theair-conditioning circuits are flushed with a washing agent thatdissolves and absorbs any in the circuits remaining soluble compoundsand flushes out any mechanical impurities. The invention also relates tothe device for carrying out this method and consisting of a pressurizedvessel containing the washing agent that is connected, through itsliquid outflow, with the flushed cooling or air-conditioning circuit,behind which there is a distilling chamber, a compressor, and acondenser connected with the liquid inflow of the pressurized vessel.

PRIOR ART

The flushing of the cooling or air-conditioning circuits is done afterpumping out the refrigerant for the purpose of removing any undesirableimpurities, mainly during maintenance or repairs.

The up to now known devices for the flushing of cooling orair-conditioning circuits function in such way, that a washing agent isflushed through the cooling or air-conditioning circuit and it dissolvesand absorbs the caught up soluble compounds and carries out mechanicalimpurities caught up in the cooling or air-conditioning circuit. Thewashing agent, which should be harmless for the environment, must havehigh solution ability and there must also exist a method for its easyregeneration—the method for separating dissolved compounds, especiallyoils and mechanical impurities.

The prior art devices for the flushing of cooling or air-conditioningcircuits work in the following way:

-   a) The washing agent repeatedly runs through the flushed cooling or    air-conditioning circuit with the aid of a liquid pump.-   b) The washing agent is enclosed in a vessel under pressure, usually    of nitrogen. A one-time run of the flushed cooling or    air-conditioning circuits is used for the flushing and the liquid is    then drained into a collection vessel.-   c) A compressor sucks vapor of the washing agent. The state of    matter usually takes place in a heat exchanger using the    condensation heat from the compressor.

The disadvantage of all prior arts devices relates especially to thelong time necessary for the process of flushing cooling orair-conditioning circuits, the weight of these devices, the flushingwith the already contaminated washing agent during the step a), theimpossibility to repeat the cycle during the step b), and theimpossibility to completely and fast remove remaining washing agent fromthe cooling or air-conditioning circuit. Possible leaks of the mediainto the environment result just in another disadvantage.

The invention's task thus is to find the method and the device for theflushing of cooling or air-conditioning circuits, which would achievethe perfect flushing of the circuits in a short time. Anotherinvention's task is achieving of the lower weight of the device and thesafe disposal of the washing agent flushed out from the cooling orair-conditioning circuits. In addition, the invention's task is also tosatisfy the function at low ambient temperatures.

SUMMARY OF THE INVENTION

The above-mentioned tasks and shortcomings of the known processes ofthis kind are, up to a certain level, resolved by the method of flushingcooling or air-conditioning circuits, during which a washing agent,dissolving and absorbing the in the cooling or air-conditioning circuitscaught up compounds and flushing out mechanical impurities, runs throughthe flushed cooling or air-conditioning circuits, that has been based onthis invention. The invention suggests flushing of cooling orair-conditioning circuits with a washing agent circulating within anenclosed cycle, without the occurrence of any outside leaks, thanks tothe different pressures between the pressurized vessel and thedistilling chamber and, after the cleaning in the distilling chamber,thanks to the pressurizing by the compressor and cooling down in thecondenser. Then, the process returns the agent back into the pressurizedvessel.

It is considered an advantage that the washing agent runs through theflushed cooling or air-conditioning circuit in the pulse way as itincreases the washing intensity and makes the releasing of impuritieseasier.

It is also advantageous, from the energy savings' point of view, whenthe washing agent goes through a heat exchanger inside the distillingchamber between the compressor and the condenser.

To ensure the maximal speed of the removal of the washing agent from theflushed cooling or air-conditioning circuit, it is advantageous when thewashing agent is pushed out of the flushed cooling or air-conditioningcircuit in the liquid state directly into the distilling chamber by thepressure difference between the gaseous stage in the pressure vessel andthe distilling chamber.

The invention relates also to the device for flushing cooling orair-conditioning circuits for performing said method. The deviceconsists of the pressure vessel containing the washing agent connectedthrough its liquid outflow with the flushed cooling or air-conditioningcircuit, behind which there is the compressor and the condenserconnected, which condenser is connected with the liquid inflow to thepressure vessel. The subject matter of the consist in that thedistilling chamber is interposed between the flushed cooling orair-conditioning circuit and the compressor and there is pressurisedinert gas in the pressure vessel above the washing agent.

For the control of the facility and the achievement of the pulse flow ofthe washing agent, it is also beneficial when there is the firstsolenoid valve interposed between the flushed cooling device and thepressure vessel, while the second solenoid valve can be interposedbetween the flushed cooling device and the distilling chamber.

The placement of a level gauge inside the distilling chamber, whichmeasures the washing agent's level, is also advantageous. It allows forthe control of solenoid valves.

Further, the fact that there is a heat exchanger inside the distillingchamber, in between the compressor outflow and the condenser, isadvantageous because of the lower consumption of energy.

The method and the device according to the invention are based on thefast flow of the washing agent through the cooling or air-conditioningcircuits preferably with the aid of different pressures between thepressurized vessel and the distilling chamber. It results in anegligible dependence on the compressor output as the requiredperformance is achieved even with the use of a low performancecompressor and at low ambient temperature.

The overpressure in the pressurized vessel is also used for the fastpush out of the liquid pure washing agent from the flushed cooling orair-conditioning circuit into the distilling chamber.

DRAWINGS

The invention is also clarified with the example of its embodimentsillustrated on the enclosed drawing, which shows the block device schemeof the flushing of cooling or air-conditioning circuits.

EXAMPLES OF THE INVENTION EMBODIMENTS

The device for the flushing of cooling or air-conditioning circuits 27,according to the invention, consists of a pressurized vessel 9, whichcontains a washing agent—for example, Genesolv® by Honeywell. The volumeof the liquid washing agent in the pressurized vessel 9, kept underpressure by the filled up gas area in the pressurized vessel 9, abovethe washing agent level, with, for example, nitrogen under 5 bars, isreliably higher (e.g. by 30%) than the assumed volume of the flushedcooling or air-conditioning circuit 27. The pressurized vessel 9 isequipped with at least one outflow 91 for the liquid, which goes down tothe bottom of the pressurized vessel 9, and at least one (preferably acouple) outflow 92 (and 93) for gas ending in the gas area in thepressurized vessel 9, above the washing agent level. There is the valve20 connected with the outflow 91 for the liquid, behind which the firstconnection 17 is placed. Then, there is the first solenoid valve 8,through which the washing agent runs to the first sight-glass 7 and tothe flushed cooling or air-conditioning circuit 27, which has been onlyschematically illustrated. After running through the cooling orair-conditioning circuit 27, the contaminated washing agent runs behindthe second sight-glass 6 to the second solenoid valve 21, in front ofwhich its pressure is measured by the first manometer 16. The washingagent runs through this second solenoid valve 21 to the bottom of thedistilling chamber 1, which is equipped with a heater 4, for example anelectric one. The washing agent having typically the boiling point, atthe atmospheric pressure, of about 15° C. heats up and evaporates. It issucked from the upper part of the distilling chamber 1 into thecompressor 14, from which it runs through the back check-valve 25 andthe oil separator 12 to the heat exchanger 3. It helps there in heatingup the distilling chamber 1. Then, it runs to the condenser 11 with themarked fan, behind which there is the second manometer 13 connected. Theliquid washing agent runs from the condenser through the secondconnection 18 and the second valve 19 back into the pressurized vessel9. The oil outflow of the separator 12 could go through the fourthsolenoid valve 15 back to the sucking side of the compressor 14.

There is a high pressure pressostat 10 connected behind the compressor14 as well as the first emptying valve 28 connected with the hose 26.The distilling chamber 1 is equipped in its bottom with the second valve5 emptying impurities and oil. Inside the distilling chamber 1, thereis, above the heat exchanger 3, the level gauge 2—for example, afloat—and the safety thermostat 24 fitted on the wall. Inside thedistilling chamber 1, on the heater 4, there is the heater thermostat 23fitted.

The performance of the device for the flushing of cooling orair-conditioning circuits, according to the invention, conforming to thedescribed example is as follows:

The liquid washing agent is stored in the vessel 9 pressurized withnitrogen up to the pressure in order of 5 bars, up to the maximumcapacity of 2 thirds of its volume. The volume of the washing agent inthe pressurized vessel 9 is by at least 30% higher than the assumedvolume of the flushed cooling or air-conditioning circuit 27, includingthe connection hoses and the distilling chamber 1.

After the connection of the flushed cooling or air-conditioning circuit27 with the circuit with the inflow IN and the outflow OUT, thecompressor 14 must, at first, pump out air from the flushed cooling orair-conditioning circuit 27 and from the distilling chamber 1. This airis emptied through the hose 26 and the first emptying valve 28. The backcheck-valve 25 is closed during this process. The air is sucked out tothe approximate pressure of 0.5 bars.

The first solenoid valve 8 and the second solenoid valve 21 open up andthe washing agent flows through the flushed cooling or air-conditioningcircuit 27 to the distilling chamber 1 at the speed created by thedifference between the pressures in the pressurized vessel 9 and thedistilling chamber 1. The compressor 14 runs at the same time and theheater 4 is heating. As soon as the distilling chamber 1 fills up, thelevel gauge 2—for example, a float—closes the solenoid valves 8 and 21.The washing agent in the distilling chamber 1 heats up to the boilingpoint and the vapors are sucked out by the compressor 14 and led throughthe heat exchanger 3 to the condenser 11, and then, condensed, back tothe pressurized vessel 9. Only a single cycle is usually necessary forthe flushing of the cooling or air-conditioning circuit 27, but theprocess can be repeated.

The process is finished by the opening up of the third solenoid valve22, when the first solenoid valve 8 is closed and the second solenoidvalve 21 is opened. Pressurized nitrogen in the pressurized vessel 9pushes the liquid washing agent into the distilling chamber 1, where theagent could be effectively heated up and distilled.

Because of the boiling point of the washing agent, which is typically15° C. in the case of Genesolv® at the atmospheric pressure, it ispractically impossible to evaporate the liquid from the flushed coolingor air-conditioning circuit 27 without the described process, especiallyat low ambient temperatures.

It is important for the effective performance of the device according tothe invention that the clean washing agent always returns back to thepressurized vessel 9 after the distilling in the distilling chamber 1.This results in flushing of the cooling or air-conditioning circuit 27always with the pure washing agent.

The speed of the washing agent flow in the flushed cooling orair-conditioning circuit 27 depends mostly on the difference betweenpressures in the pressurized vessel 9 and the distilling chamber 1. Itdepends only negligibly on the compressor 14 output, which does not haveto be high.

The flushing of the cooling or air-conditioning circuit 27 takes placein pulses caused by opening up and closing down of the solenoid valves 8and 21. These pulses, in connection with the high speed of the washingagent flow, guarantee perfect flushing of the cooling orair-conditioning circuit 27 in a short time.

The pressurized vessel 9 is equipped with at least one separated outflow91 for the liquid and one, or two outflows 92 and 93 for gas. It ispressurized with nitrogen.

The distilling chamber 1 is heated up by the heater 4—for example anelectric one, the heater thermostat 23, and the heat exchanger 3managing the discharge from the compressor 14. The washing agent levelin the distilling chamber 1 is controlled by the level gauge 2, forexample, a float. The distilling separates the washing agent from oil,mechanical impurities, and, partly, from water. The reminder of theliquid washing agent from the flushed cooling or air-conditioningcircuit 27 is pushed out into the distilling chamber 1 on the end of theprocess, thanks to impacts of pressurized nitrogen, caused by theopening up and closing down of the third solenoid valve 22. This, at thesame time, also removes any remaining mechanical impurities and theliquid washing agent. This design fundamentally speeds up the process,especially at low ambient temperatures.

1. A method of flushing a cooling or air-conditioning circuit, duringwhich a washing agent running through the cooling or air-conditioningcircuit dissolves and absorbs in the cooling or air-conditioning circuitcaught up compounds and carries out mechanical impurities, the methodcomprising circulating the washing agent in the cooling orair-conditioning circuit within an enclosed cycle and without anyoutside leaks, due to a difference in pressures between a pressurizedvessel and a distilling chamber and returning back the washing agent tothe pressurized vessel after its cleaning in the distilling chamber,pressurized by a compressor, and cooling down in a condenser, whereinduring circulating the washing agent, the washing agent exits thedistilling chamber and is routed through the compressor and then backthrough the distilling chamber before the washing agent once again exitsthe distilling chamber and is routed to the condenser.
 2. The methodaccording to claim 1, wherein the washing agent is pulse circulated in asluiced cooling or air-conditioning circuit.
 3. The method according toclaim 1, wherein the washing agent runs between the compressor and thecondenser through a heat exchanger in the distilling chamber.
 4. Themethod according to claim 1, wherein the washing agent is pushed outfrom the cooling or air-conditioning circuit in a liquid state directlyto the distilling chamber by the difference in pressures in a gas stagein the pressurized vessel and the distilling chamber.
 5. A device forthe flushing of the cooling or air-conditioning circuit for performingthe process, according to claim 1, the device comprising the pressurizedvessel containing the washing agent, which is connected through a liquidoutflow with the cooling or air-conditioning circuit, behind which thereis the compressor and a condenser connected through a liquid inflow withthe pressurized vessel, wherein the distilling chamber is fitted betweenthe cooling or air-conditioning circuit and the compressor and whereinpressurized inert gas is in the pressurized vessel above the washingagent.
 6. The device according to claim 5, wherein a first solenoidvalve is inserted between the cooling or air-conditioning circuit andthe pressurized vessel and a second solenoid valve is fitted between thecooling or air-conditioning circuit and the distilling chamber.
 7. Thedevice according to claim 6, wherein a washing agent level gauge isplaced inside the distilling chamber, which controls the first andsecond solenoid valves.
 8. The device according to claim 7, wherein aheat exchanger is fitted between a compressor outflow and the condenserand the heat exchanger is placed in the distilling chamber, in whichabove the heat exchanger the washing agent level gauge is positioned.